import React, { Component } from 'react'
import PropTypes from 'prop-types'
import {nanoid} from 'nanoid'
import './index.css'

export default class Header extends Component {

  //对接收的props进行:类型，必要性的限制
  static propTypes = {
    addTdo: PropTypes.func.isRequired
  }

  handleKeyUp = (event) => {
    //解构赋值获取keyCode,target
    const {keyCode,target} = event
    //判断是否是回车键
    if (event.keyCode !== 13) return
    //添加的todo名字不能为空
    if (target.value.trim() === ''){
      alert('输入不能为空')
      return
    } 
    //准备好一个todo对象
    const toboObj = {id:nanoid(), name:target.value, done:false}
    //将todoOjb传递给App
    this.props.addTdo(toboObj)
  }

  render() {
    return (
      <div className='todo-header'>
        <input onKeyUp={this.handleKeyUp} type="text" placeholder='输入你的任务名称,按回车键确认'/>
      </div>
    )
  }
}
